Lining for perforated cartridge cases



United States LINING FOR PERFORATED CARTRIDGE CASES Arnold J. Tuckerman, Philadelphia, Anthony Gallaccio, Havertown, and Morton Kushner, Philadelphia, Pa.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to a lining for cartridge cases, particularly perforated cartridge cases for recoilless rifles, and a process of manufacturing such a cartridge case linin It is an object of this invention to provide a lining which affords a seal adjacent the inner end of a cartridge case surrounding the primer seat, a seal for the perforations through the side walls of the cartridge case, and a seal adjacent the open end of the cartridge case beneath the projectile carried therein.

It is a further object of this invention to provide a lining for a cartridge case, which lining is readily applied to the case, provides a maximum of room within the case because the lining is itself a thin wall, affords improved sealing against moisture or other agents harmful to the explosive charge in the cartridge case, burns completely upon firing the round of which the cartridge case forms a part, and facilitates the manufacture of such cartridge cases because of the reduced number and simplicity of the operations involved.

For a further exposition of this invention, reference may be had to the annexed drawing and specification at the end of which the novel features of this invention will be pointed out and claimed.

In the drawings:

Fig. 1 is a side elevation with the mouth of the lining left open.

Fig. 2 is a longitudinal cross section on an enlarged scale on line 2-2 of Fig. 1 through the wall of the cartridge case and the lining thereon.

Fig. 3 is a transverse cross section on the same scale as Fig.2on line 33 of Fig. 1.

Process One example of our improved process is the following. We take a plasticized polyvinyl chloride jell dispersion and add methyl-iso-butyl ketone as a solvent until the resulting mixture has a solid content of approximately 18% by weight. Other solid materials, which may be used in place of polyvinyl chloride, are any vinyl-type plastics. Solvents, which may be used instead of the methyl-iso-butyl ketone, are other ketones, preferably those boiling at about 100 to 150 C. The above-referred to admixture is then heated to a temperature less than 95 C. until the viscosity is suitable for a solid to be readily dipped into it.

A hollow tube is then force-fitted into the primer opening of a perforated cartridge case. The perforated cartridge case is then dipped (month end first) into the hot polyvinyl chloride admixture. This can be done by grasping the tube in the hand. The case is then slowly withdrawn from the admixture in a vertical position so as to secure as uniform as possible a layer of polyvinyl chloride on both the inner and outer surfaces of the cartridge case. The coatings on the inner and outer walls of the cartridge case coalesce or unite in the perforations on the side walls of the case sealing each of these perforations with a transparent film or pane. The cartridge case is only dipped into the admixture to a sufficient depth so that the films adhere to the inner and outer faces of the side wall of the cartridge case between the closed or primer end and the adjacent holes. No coating is applied to the closed or primer end through atent ice which the primer seat extends. However, the bond between the film and the side walls of the cartridge case is ample to seal this end of the cartridge case.

Immediately after its withdrawal from the hot admixture the cartridge case is rotated either in a horizontal position, a vertical position, or a position with the axis of the cartridge case at an intermediate angle between the vertical and horizontal. The position which is selected is chosen to secure as uniform a thickness of the coating as possible. This rotation is continued until the film sets. The films constituting the lining are then allowed to dry in air for approximately one hour at room temperature. The solvent (methyl-iso-butyl ketone) is then driven off by heating the cartridge case and the lining in an oven for approximately 24 hours at a temperature of 55 C. until the lining is properly cured. Next, the cartridge case and the lining are allowed to cool to room temperature. The outer layer of the lining is then cut circumferentially between the open mouth of the cartridge case and the nearest perforations. This portion of the lining is then stripped away from the wall of the cartridge case so that it forms a bag or bellows mouth projecting from the open end of the cartridge case. The case is then loaded with the powder or other propellent explosive which it is to contain. The cartridge case is sealed by stuffing the bag or bellows mouth of the lining into the open end of the cartridge case, or by causing the walls of the bag or bellows end of the cartridge case to adhere together by the use of a solvent or heat, or by tying.

It will thus be seen that the lining of this invention provides a seal encircling the case wall between the primer seat and the nearest perforations, a seal for each of the perforations through the side wall of the cartridge case, and a seal for the lining adjacent the open or month end of the cartridge case.

The above-mentioned process is described and claimed in applicants copending divisional application, Serial No. 148,442, filed March 8, 1950.

Cartridge case and lining The selected embodiment of the cartridge case and lining shown in the drawings and manufactured according to the foregoing process comprises a cylindrical cartridge case I, preferably of metal, having an open or month end 2 and a primer or closed end 3 having a perforation or primer seat 4 passing through the closed end. For use with a recoilless rifle the cartridge case has a number of perforations 5 through its side walls. For simplicity, only a few of these perforations 5 are shown in Fig. 1. As is best seen in Figs. 2 and 3, the interior of the cartridge case is covered with a layer or film 6 and the outer surface of the cartridge case is covered (except adjacent the open end 2) with a layer or film 7. These layers or films 6 and 7 coalesce or unite to form a pane or seal 8 filling and bridging the side wall perforations 5. Layers or films 6 and 7 and the panes or seals 8 integral therewith afford a seal against moisture or other agents harmful to the explosive charge in the cartridge case. This seal burns when the explosive charge is fired and does not foul or otherwise damage the recoilless rifle or the cartridge case which forms a part of the ammunition therefor since the burnt film dissipates forming only a negligible residue or ash.

It is readily understood that many modifications of the foregoing process and article are possible within the scope of this invention. No limitation is to be implied because of the illustrative examples heretofore given or for any other reason save as the scope of appended claims express. For example, the case need not be a cartridge case but may be a package or container for other materials than combustible powder.

We claim:

1. A cartridge case having a film of plastic material adherent to the major part of the inner face of its side wall and the outer face of its side wall and forming a bag or bellows mouth adjacent the open or month end of the cartridge case.

2. A lining for a metal cartridge case comprising a layer or film of combustible material adherent to the major part of the inner face of the cartridge case side wall, a layer or film of the same material adherent to the outer face of the cartridge case and a continuation of said inner film forming a bag or bellows mouth projecting through the open end of the cartridge case.

3. A lining for a perforated cartridge case for a recoilless rifle comprising, a film of flexible combustible plastic adherent to the inner surface of the cartridge case, a film of the same material adherent to the outer surface of the cartridge case and coalesced with the inner film to form a seal or pane in each of the perforations through the side wall of the cartridge case, and a portion of the inner layer extending out of the open end of the cartridge case and adapted to be sealed adjacent said open end.

4. Recoilless rifle ammunition including, a cartridge case having perforations through its side walls, and a film of a resilient combustible plastic material integral with and sealing each of said perforations.

5. In recoilless rifle ammunition including a metallic cartridge case having perforations through its side wall, a lining comprising a seal of polyvinyl chloride integral with and closing each of said perforations.

6. Ammunition for a recoilless rifle including a perforated cartridge case and a coating of polyvinyl chloride adherent to the surfaces of the side walls of said cartridge 25 case and sealing the perforations through said side walls.

7. A lining for a case comprising, a layer or film of resilient plastic material adherent to the major portion of the outer face of the case and adherent to the major References Cited in the file of this patent UNITED STATES PATENTS 503,096 Mohr Aug. 8, 1893 1,669,969 Caruth May 15, 1928 1,929,453 Semon Oct. 10, 1933 2,353,934 Schreib July 18, 1944 2,379,056 Alexander June 26, 1945 2,431,684 Brophy Dec. 2, 1947 2,441,227 Pineles May 11, 1948 FOREIGN PATENTS 502,770 Great Britain Mar. 24, 1939 OTHER REFERENCES Recoil Elimination, pages 236, 237 of Army Ordnance, September-October, 1945. Published by Ann. Ordnance Assn., Penn. Avenue at 17th Street. NW., Washington 6, D. C. (Copy in 102/3 8.) 

